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[An unusual series of complications in therapy with implantable cardioverter-defibrillator]
Insights
Implantable cardioverter-defibrillator (ICD) oversensing due to insulation defects caused inappropriate shocks. Early detection and replacement of faulty components are crucial for effective ICD therapy.
Area of Science:
- Cardiology
- Biomedical Engineering
Background:
- A 48-year-old male with dilative cardiomyopathy and ventricular fibrillation history received an implantable cardioverter-defibrillator (ICD) in 1990.
- Early battery depletion necessitated a generator exchange, followed by recurrent inappropriate shocks.
Observation:
- Despite comprehensive diagnostics, the cause of inappropriate shocks remained elusive for months.
- Repeated beepograms eventually revealed oversensing, leading to generator and transvenous sensing electrode replacement.
Findings:
- An insulation defect in the sensing electrode, near the generator, was identified as the cause of oversensing.
- Following replacement, the patient experienced appropriate shocks for presyncope and is now stable.
Implications:
- Implantable cardioverter-defibrillator (ICD) therapy requires specialized centers due to its complexity.
- Thorough investigation and component integrity are vital for preventing device malfunction and ensuring patient safety.
Abstract:
A 48-year-old man with dilative cardiomyopathy and a history of resuscitation due to ventricular fibrillation received an implantable cardioverter-defibrillator (ICD) with epicardial sensing and defibrillation electrodes in March 1990. An early battery depletion due to increased electrical leakage of a filter capacitor necessitated a generator exchange in July 1990. Subsequent inappropriate discharges occurred, but no underlying cause could be documented by history, clinical examination, Holter monitoring, and beepograms. Only 3 months later was it possible to demonstrate oversensing by repeated beepograms, and a new generator and transvenous sensing electrode were implanted in October 1991. Four months later, inappropriate shocks were suspected again. Once more, history, clinical examination, Holter monitoring, and beepograms were without pathological result. At follow-up, repeated beepograms during exercise demonstrated an oversensing, and an insulation defect of the newly implanted sensing electrode close to the edge of the generator could be documented on x-ray. Since replacement of generator and sensing electrode in July 1992 the patient is doing well. He received two appropriate shocks which were associated with presyncope. ICD therapy is very complex and therefore should only be performed in centers providing the necessary personal, apparative and logistic conditions.